Various conference supporting systems are proposed so as to share a document screen among a plurality of terminals and to be used in a conference such that each user inputs notes on the terminal by handwriting during the conference. In such a conference supporting system, when two or more handwriting inputs are performed simultaneously on the same area in the document screen via a plurality of terminals, two or more pieces of information inputted by handwriting are displayed so as to overlap with each other on the same area, which lowers the readability of them. Further, in order to prevent a self terminal and other terminals from performing respective handwriting inputs simultaneously, it is required to perform a handwriting input on the self terminal while confirming the timing and area of each of handwriting inputs performed by the other terminals at every time. Accordingly, smooth discussion and information exchange in a conference are disturbed.
For such problems, for example, WO 2008/132977 discloses an image editing apparatus which includes an input section which inputs information with regard to at least an existing object or a new object; a display section which displays at least the existing object or the new object; an overlap detecting section which detects an overlap between the existing object and the new object; a selecting section which selects whether or not to overlap the existing object and the new object; and a moving section which moves the existing object to the outside of the area of the new object so as to make the existing object not to overlap the new object based on the information input by the input section.
Further, Japanese Unexamined Patent Publication (JP-A) No. 2010-267218 discloses a conference supporting system which includes a plurality of terminal units and an exclusive control apparatus. The conference supporting system is configured to enable each of the plurality of terminal units and the exclusive control apparatus to perform mutual transmission and reception of data to be written in a display page where conference material data is displayed. The conference supporting system is further constituted as follows. That is, each of the plurality of terminal units includes a requesting section and a display section. The requesting section is configured to determine partially an area in a display page which is displayed on the self terminal unit and shows the conference material data and to make a request for write permission to the area to the exclusive control apparatus. The display section is configured to display the data transmitted from the exclusive control apparatus on the display page of the conference material data out of various write data transmitted to the exclusive control apparatus from the input terminals. The exclusive control apparatus includes a request receiving section, an exclusive control section and a transmission control section. The request receiving section is configured to receive the request for the write permission from each of the terminal units. The exclusive control section is configured to grant the write permission to the terminal unit making the request under the condition that the area determined in the request for the write permission does not overlap with other areas whose write permissions have already been granted to other terminal units than the terminal unit making the request, and is configured not to grant the write permission to the terminal unit making the request under the condition that those areas overlap together. The transmission control section is configured to confirm the data received from the plural terminal units, transmit the received data to the plural terminal units under the condition that the received data arc write data transmitted from the terminal unit which has write permission of the area whose write permission has been granted, and forbid the data from being transmitted to the plural terminal units under the condition that the received data are data from a terminal unit other than the terminal unit having write permission of an area overlapping with the area whose write permission has been granted.
Furthermore, JP-A No. 2006-303742 discloses an electric device which includes a setting section, a display section, a control section and a communicating section. The setting section is configured to set two or more devices connectable to each other through a communication network as members of a group. The display section is configured to display a hoard on which data shared among the devices set as the members of the group are written. The control section is configured to write data inputted by a device having a specific right and selected from the devices set as the members of the group on the board and to update the data on the board. The communicating section is configured to distribute the data written on the board to each of the devices set as the members of the group.
With the technique of WO 2008/132977, when an existing object and a new object overlap with each other, the existing object is moved to the outside of the area of the new object. Therefore, the overlapping between the objects can be prevented. However, in this method, since the existing object may be moved against the intention of a user, which makes a problem that contents of the display screen intended by the user cannot be obtained.
Further, with the technique of JP-A No. 2010-267218, when the areas overlap with each other, the exclusive control is performed so as not to grant write permission to the terminal unit making the request for the write permission. Therefore, it is possible to prevent two or more terminal units from writing data into the same area. However, in this method, write permission is granted to only a single user for one area. Accordingly, the other users belonging to the same group cannot perform writing for the area, which makes a problem that discussion and information exchange cannot be performed efficiently. Further, in the case the determined areas overlap with each other, users are required to determine an area again to acquire the permission, which makes a problem that the operation becomes complicated.
Furthermore, with the technique of JP-A No. 2006-303742, the data written on the board are distributed to each of the devices set as the members of the group. Therefore, the data can be shared among the members. However, in the method, the writing on the board screen is limited to a user having write permission, and the other users cannot perform writing for the board unless the write permission is transferred thereto. Accordingly, there is a problem that discussion and information exchange cannot be performed efficiently. The present invention seeks to solve the problems.